Can I configure the NGW-1?

NMEA Reader contains all the currently available configuration options for the NGW-1.

In the majority of cases, configuration of an NGW-1 is not required as it communicates at the standard 4800 baud rate for NMEA 0183 devices (38400 for the AIS firmware) by default. All available conversions are enabled by default so the only conversion related configuration option is to reduce the number of conversions carried out by the NGW-1. Checking extra boxes in the PGN enable lists in NMEA Reader that weren’t initially checked will have no effect.

All available conversions being enabled on the NGW-1 should not cause conflicts as NMEA 0183 devices are usually good at recognising data that they don’t require and ignoring it. NMEA 2000 is also very good at handling data.

For full instructions on how to use NMEA Reader, please refer to the “NMEA Reader & EBL Reader User Manual Issue 1.00.pdf”. In the manual it shows the hardware configuration option as a window, however with the latest edition of NMEA Reader it is a tab that can be selected at the bottom left side of the NMEA Reader window.

As a quick description: Using NMEA Reader, you can choose which PGN’s are received (Rx) or transmitted (Tx) by the NGW-1. For example, turning off PGN 127251 from the “Rx PGN Enable List” will stop all ROT sentences appearing on the NMEA 0183 output of the NGW. However, turning off PGN 128267 from the “Rx PGN Enable List” will stop both DPT and DBT sentences appearing on the NMEA 0183 side of the NGW. There is currently no way of choosing DPT or DBT, you can only get or stop both.

The “Tx PGN Enable List” works in a similar way, DBT and DPT are used to generate PGN 128267 you cannot choose data from one sentences and not the other. Please refer to the NGW-1 Conversion List document to fully understand the relationship between the NMEA 2000 PGN and the NMEA 0183 Sentences.

Only the USB variant of the NGW-1 is capable of baud rates of 115200 Baud and above. Changing the Baud rate of non USB variants to 115200 Baud or above will prevent the NGW-1 from communicating and will require assistance from Actisense tech support.

See question number 4 for details on how to connect your NGW-1 to a PC.

Can I connect multiple Listeners to an NGW-1?

The NGW-1 talker port can drive up to 20mA. This means that potentially up to 10 NMEA Listeners can be connected to the NGW-1 output. Check the input currents of each Listener to see how many can be connected together.

Note that many NMEA Listeners do not provide isolation on their inputs. Connecting these together can cause ground loops and thus damage to the Listener ports of these devices. For safe connection of multiple Listeners our NBF-3 NMEA Buffer is recommended.

Can I connect multiple Talkers to an NGW-1?

No, it is not possible to connect multiple Talkers to a NGW-1’s Listener port. (This is in accordance with the NMEA 0183 specification). You can use an NMEA multiplexer like the NDC-4 to combine multiple NMEA 0183 streams together to put into the NGW-1. Alternatively, using more than one NGW-1 is the recommended option.

Note: three NGW-1’s cost approximately the same as one NDC-4 plus one NGW-1.

Can I connect a different Listener and Talker to the NGW-1’s NMEA 0183 port?

It is possible to connect an NMEA Listener to the NGW-1 Talker port and a different NMEA Talker to the NGW-1 Listener port. Note that both NMEA 0183 devices connected to the NGW-1’s NMEA 0183 port must have the same baud rate set.

Is there isolation between all the ports?

What versions of NMEA 0183 are supported?

The NGW-1 supports all versions of NMEA 0183. Devices that use RS232 or RS422 voltage levels are accepted and connections that use ground or differential connections are suitable. The NGW-1 automatically adapts to the electrical requirements of the connected devices.

How do I connect my ISO-Drive variant NGW-1 to a PC?

When connecting an NGW-1 with an ISO-Drive to a PC there are three options:

Wire a D-type 9-pin connector and cable to your NGW-1’s NMEA 0183 (ISO-Drive) port – you can connect that directly to the NGW-1 cable terminals inside the case if that is more convenient. Plug that cable in to a standard RS232 port, or a “USB to Serial” adapter cable if your computer does not have an RS232 port. Please refer to “Figure 2” on page 7 of the NGW-1 User Manual.

You might want to consider theActisense DB9-F and USB-1 products if do not have cables already.

For a quick and easy connection, use theActisense USG-1 for direct wiring to the NGW-1’s cable terminals whilst keeping your PC safe with 1500 volts of isolation. You can use the USG-1 as a safe way to connect any NMEA 0183 signal to your PC so it is ideal as an “NMEA 0183 diagnostic tool” when used with our freely available NMEA Reader software.

If the NGW-1 is not connected to an NMEA 2000 network, an alternative NGW-1 power source is required: 12/24 volt power can be connected directly to the “Net S” and “Net C” terminals inside the NGW-1-ISO case.

Can I change/update the firmware in my NGW-1?

Yes you can. To change/update firmware, please follow these instructions:

Locate and download the required ActiPatch from the Actisense website. For example, if you have an NGW-1-STNG and you wish to enable AIS conversions, you will need “NGW-1-STNG-AIS v2.420 ActiPatch Setup.exe”

To connect your NGW-1 (ISO Variants) to a PC (to update its firmware) you have the following options:

Wire a D-type 9-pin connector to your NGW-1’s NMEA 0183 port (you can connect that directly to the NGW-1 terminals inside the case if that is more convenient), and then connect to a standard “USB to Serial” adapter cable if your computer does not have an RS232 port on it. Please refer to the NGW-1 User Manual for wiring instructions.

‘D-type 9-pin’ connectors are available from an Actisense dealer. USB to serial converters can be purchased from Amazon

For a quick and easy connection, use our Actisense USG-2 product for direct wiring to the NGW-1’s terminals whilst keeping your PC safe with 1500 volts of isolation.You can use the USG-2 as a safe way to connect any NMEA 0183 signal to your PC so it is great as an NMEA 0183 diagnostic tool when used with our freely available NMEA Reader software

Note that with the ISO variants of the NGW-1, power needs to be present on the NMEA 2000/SeaTalkNG side of the NGW-1 for the PC connection to be powered and active. The USB variants are powered once the latest USB drivers have been successfully downloaded and installed.

With the NGW-1 connected to your PC, select the correct COM port for your NGW-1 from the drop down menu in the Actipatch you just downloaded.

Click on the ‘Program’ button when it goes green and you will see the progress bar indicating the installation of the firmware to your NGW-1.

When the installation is completed successfully, the ‘Patch ID’ box and ‘Device ID’ box will contain identical information.

What conversions are supported by the NGW-1?

The NGW-1 Conversion Lists are available on the download page – there is one list for the standard firmware variants (NGW-1-ISO, NGW-1-USB and NGW-1-STNG) and one list for the AIS firmware variants (NGW-1-

ISO-AIS and NGW-1-USB-AIS). Each Conversion List details which conversions are supported by the specified NGW-1 firmware version. Updating the NGW-1 between the standard firmware and AIS firmware (using the ActiPatch program) switches between the two Conversion Lists. The latest NGW-1 firmware can be found on the firmware page.

New conversions are being developed – Actisense welcomes suggestions and requests for future updates.

How is the NGW-1 Powered?

All ISO-Drive variants (NGW-1-ISO, NGW-1-ISO-AIS and NGW-1-STNG) are completely powered from the NMEA 2000 network and have an NMEA 2000 LEN of 1 (50 mA or less). Once connected to a powered and terminated NMEA 2000 network, the NGW-1-ISO LEDs will flash.

All USB variants (NGW-1-USB and NGW-1-USB-AIS) takes most of their power from the USB connection and also have an NMEA 2000 LEN of 1 (50 mA or less). The LEDs will not flash until the USB drivers have been successfully installed (allowing the OS to enable USB power).

All ISO-Drive variants (NGW-1-ISO, NGW-1-ISO-AIS and NGW-1-STNG) have stripped and tinned wires at the end of a high quality 1.5 metre cable to accommodate varying installation requirements to an NMEA Talker and/or NMEA Listener.

All USB variants (NGW-1-USB and NGW-1-USB-AIS) have a 1.5 metre standard USB cable with a USB A plug on the end for easy connection to a computer or USB hub.

The NGW-1-ISO is the standard option applicable to the majority of customers. The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-ISO-AIS is an NGW-1-ISO pre-configured for use with an AIS device. The NGW-1-AIS Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-USB is the option typically used with PC software that only understands NMEA 0183 (i.e. it is not compatible with the Actisense NGT-1). The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-USB-AIS is an NGW-1-USB pre-configured for use with PC software that only understands NMEA 0183 and needs or supplies AIS information. The NGW-1-AIS Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-STNG is the Raymarine SeaTalkNG option: The kit includes an NGW-1-ISO and a SeaTalkNG to NMEA 2000 adapter cable (STNG-A06045) allowing the NGW-1 to be connected directly to the Raymarine SeaTalkNG network – providing seamless integration with Raymarine products. The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

As of April 2015, a SeaTalkNG to NMEA 2000 adapter cable (STNG-A06045) can be purchased with an NGW-1-ISO, NGW-1-ISO-AIS, NGW-1-USB or NGW-1-USB-AIS to allow direct connection toa Raymarine SeaTalkNG network

USG-2 USB to NMEA 0183 Gateway

How waterproof is the USG-2

The internal electronics of the USG-2 are potted and sealed to provide a high level of water/ingress protection. The high quality, shielded USB lead included with the USG-2 also provides a similar, high level of water protection when mated with the high retention USB receptacle.

If the device is going to be used in an environment where it is going to be subjected to direct contact with water splashes etc. then it is recommended as a preventative measure that silicone grease (or dielectric grease) is used.

What features exist to aid fault finding?

Can I connect more than one Talker (transmitting device) to the USG-2?

No. It is not possible to connect more than one Talker to a Listeners input in any NMEA 0183 network. A multiplexer, such as the Actisense NDC-4, is required to combine multiple Talker outputs in to one.

Can I connect more than one Listener (receiving device) to the USG-2?

Yes. The USG-2 will support up to eight Listeners (depending on the demand from the Listener). To ensure safe isolation of all Listeners and that enough power is available, we recommend the use of an Actisense NBF-3.

Can I connect devices to the USG-2 that communicate at different baud rates?

Can I buy a third party USB lead to use with the USG-2?

While a standard type B USB plug can be used with the USG-2, this is not recommended. Standard USB leads will not provide the same level of ingress protection that the Actisense USB lead has been designed to as it is provided with a rubber ‘O’ ring seal on the connection to the USG-2.

What is the default baud rate of the USG-2?

NDC-4 NMEA Multiplexer

I do not have a serial port on my laptop computer. How can I connect the NMEA Data Multiplexer?

If you have already purchased an NDC-4, Actisense offers a ‘USB kit’ that can convert the standard NDC-4 into an NDC-4-USB. Please contact Actisense or your nearest distributor for pricing and availability of the ‘USB kit’.

Alternatively, If you have not already purchased an NDC, the new NDC-4-USB has a USB port built in for easy connection to a PC.

Simple Plug’n’Play installation and operation makes either of these options a perfect solution.

My GPS unit can output its data at a baud rate of 9600bps. How can do I configure the NDC to accept this baud rate?

By default, the Actisense NDC-4 uses the NMEA 0183 default communication speed of 4800 Baud (bits per second) for all of its NMEA input ports.

However, if the users GPS unit allows the data to be output at 9600 Baud / BPS, then the Actisense NDC-4 can be configured (using the Control Centre PC software) to accept this as an input. This will reduce the time taken for the GPS unit to transfer the data to the Actisense NDC and so allow more time to handle the data.

All the NMEA input ports (except for input 4) can have their Baud rates set to any standard rate between 4800 and 38400 (for NMEA high-speed v3.0 support). They also offer the option to set the Baud rate to 57600 – allowing for future support of very high speed AIS transponders.

Please note that the Baud rate of opto input 1 is shared with the ‘NMEA Data Combined’ output (ISO-Drive output 1), so the required output Baud rate must be considered when changing input Baud rate of input 1.

How can the NMEA Data Multiplexer reduce the congestion on my NMEA network?

The Actisense NDC-4 have many useful features, among which is the ability to prioritise their input ports. The usefulness of this feature becomes apparent when the NMEA network is running over 50% loading/capacity (most setups). At this point a standard NMEA Multiplexer could start to delay the important information by an unacceptable amount and may even lose it altogether.

The Actisense NDC however, will always transfer the highest priority input’s NMEA sentences first, keeping the delay to the minimum possible. The remainder of the inputs will have their NMEA sentences transferred in turn, until all data is either transferred or no more time / bandwidth is available in the NMEA output.

For example, the most relied upon unit e.g. GPS, should be attached to input port 1 (the highest priority).

The Actisense NDC-4 ‘Port Priority’ defaults follow the logical port numbering, i.e. port 1 is the highest priority and port 4 the lowest. These priorities can be re-configured as required by using the NDC Control Centre PC software – please view the downloads page to get your copy of the NDC Control Centre.

Can I use an NMEA Autoswitch with my NMEA Data Multiplexer?

Yes, is the simple answer. The Actisense NMEA Autoswitch (or an NDC-4 in ‘Autoswitch mode’) has been specifically designed to work together with the NMEA Multiplexer / Combiner NDC-4 (in ‘Combine Mode’) to create a complete NMEA system solution.

The normal NMEA system would have an Actisense NMEA Autoswitch connected to two (or more) GPS / Depth sounder units. The NMEA Autoswitch adds a special NMEA tag to the data that passes through it to help identify which of these GPS / Depth sounder units supplied the NMEA data.

The autoswitched NMEA output is connected to one of the NMEA Data Multiplexer’s inputs. In this way the highest priority device’s NMEA data is autoswitched into the complete NMEA system and the actual device supplying the NMEA data can be determined (and displayed if required and possible) to help the user.

Why would I want or need a NMEA Data Multiplexer?

The NMEA 0183 standard allows any suitably designed marine electronic device to share its gathered information with any other device on a vessel. Unfortunately, there is one very large drawback with this standard – only one device on a connected network can actually send data (a single ‘talker’ device), with multiple devices (determined by the current limit of the sending unit) listening to that data (multiple listeners).

If the vessel owner has an instrument that ideally requires the data output of two or more devices, for example a chart plotter, then the owner has no alternative but to settle on connecting only the most important device, usually the GPS.

What happens if the owner prefers the vessels gyro compass output to that of the GPS, or requires that the current depth be displayed on the plotted chart to help avoid the possible case of running the vessel aground on a shifting sand bank? The NMEA 0183 standard cannot supply an answer to those questions: “one transmitting / talking device only”.

The Actisense NMEA Data Multiplexer NDC-4 can solve all these problems and more with its simple, easy and flexible designs.

Is the OPTO-4 a direct replacement for the PC-OPTO-3?

Can I use the OPTO-4 with a USB to serial converter cable?

Yes, simply connect the OPTO-4 female 9 pin connector to the male 9 pin connector of the USB to Serial Cable. The OPTO-4 will continue to provide isolation between the NMEA 0183 Talker and the PC. The USB to serial converter must support hardware handshaking (this is normally standard) and it must be enabled.

Can I connect two OPTO-4 cables together to get bi-directional isolation?

This is possible when connecting the wire ends together, but not when connecting the DB9 connectors together. Connecting the DB9 9 pin connectors together will remove the isolation, connecting the ground of both devices together.

Connecting the wire ends together will preserve the isolation. Both OPTO-4 cables will require power on the 9 pin RS232 connector, typically provided by the RS2323 port handshaking lines.

This configuration can also be used to extend an RS232 cable from the standard 20 metres potentially up to 200 metres as was demonstrated by one customer.

What are the connections on the OPTO-4?

The RS232 end is a female 9-pin D-Sub DB9 connector following the standard 9-pin RS232 pin out specification.

The other end has bare wires. An isolated input pair A/+ and B/- for connection to an NMEA Talker, using RS422 voltage levels. A non-isolated output pair A/+ and ground for connection to an isolated listener, using RS232 voltage levels. There is also a shield wire at this end which connects through to the DB9 shield.

Can I use the OPTO-4 when the RS232 port does not provide power on the handshaking lines? Is the OPTO-4 a direct replacement for the PC-OPTO-3?

Is there bi-directional isolation?

No, only the RS232 (PC) input is isolated from the NMEA 0183 Talker. An NMEA 0183 Listener connected to the RS232 (PC) output must have an isolated input. For bi-directional isolation, two OPTO-4 cables can be connected back to back.

What if my NMEA 0183 Listener does not have an isolated input or uses ground for the negative data connection?

Isolation is provided between the NMEA Talker ground and the Listeners RS232 ground.

The OPTO-4 uses the same ground as the RS232 connection for the connection to the NMEA Listener. Connecting an NMEA Listener that is not isolated or uses ground for the return line will negate the isolation, making the OPTO-4 into a normal serial cable. To maintain the isolation that protects the devices from damage, the NMEA listener MUST have an isolated input.

Can I use the NMEA Opto-isolator for other non-NMEA uses?

The OPTO-4 cable converts the RS422 / RS485 (NMEA) voltage levels to RS232 (PC) voltage levels. Any data type can be transferred by the OPTO-4 using these voltage levels.

An example of an alternative use is to extend an RS232 cable run beyond the normal length of 20 meters. A customer has reported that using two OPTO-4 cables connected together, a cable run of 200 metres was achieved.

Two OPTO-4 cables back to back (with the RS232 connectors at each end) will also provide bi-directional isolation.

Why is isolation needed for my RS232 connection?

The NMEA 0183 specification, from version 2 and higher, requires devices to be isolated on their input lines. The OPTO-4 allows an RS232 input connection to meet these NMEA 0183 Listener specifications.

Without this protection you risk ground loop damage to the RS232 device and/or the NMEA Talker. This might result in the need to replace expensive equipment.

Does the Opto-4 need external power? Is the OPTO-4 a direct replacement for the PC-OPTO-3?

No, it takes power from the RS232 handshaking lines. Please note that this requires the RS232 port to have these handshaking lines both connected and enabled. Most full RS232 ports (provided through DB9 connectors) on PC’s will comply with this. If there are no handshaking lines on the RS232 port then see the instructions on how to connect external power in the Quick Start Guide on the OPTO-4 downloads page.

DST-2 Depth, Speed & Temperature Module

What special features does it have?

This is a very open-ended answer because, as the Actisense Active DST Module’s software can be updated, the list of special features can be extended or modified when required – by Actisense, or a particular customer.

The first special feature developed for a commercial customer was the Hydrographic firmware upgrade which enables additional proprietary NMEA 0183 data to be sent to the PC allowing a hydrographic (picture) slice of the water/seabed to be displayed in full colour, detailing the differing strengths of all echoes.

By scrolling this data every time another slice is received, a history of seabed information is built up. This display creates a detailed picture of the seabed and other echoes (potentially fish) found in the water below the transducer.

This specialist firmware and NMEA display software (for a Windows PC or laptop) is not currently available to the general public.

Please contact Actisense if this option is of interest to you or your company.

Why would I want or need an Active DST Module?

The Actisense Active DST Module was designed as the perfect solution to:

A) the situation where an existing depth sounder’s transducer is still working but the display unit controlling it is faulty and/or too old.

B) the situation where the user requires to use a non-Airmar transducer, but still wants all the benefits of the Active Transducer.

The Actisense Active DST Module, working with a large range of transducers, can supply high quality depth, speed, distance log and water temperature information (in NMEA 0183 format) to a chart plotter, radar or even an onboard PC.

The Active DST Module design is very flexible, having been tried and proven with a large range of transducers. This list is always growing, and currently includes, but is not limited to:

Airmar 170 kHz, 200kHz and 235kHz (In-hull, Thru-hull, Transom mount)

Skipper 200 kHz (In-hull)

EchoPilot Marine 150 kHz (In-hull)

NASA Marine 150 kHz (In-hull)

The proven Actisense depth sounding algorithm, working with, for example an Airmar transducer, can provide the best-in-class tracking of the seabed – capable of tracking the seabed down to 0.3 metres (1 foot) and up to 200 metres (660 feet), and still outperform other depth sounders at speeds up to 50 knots (57 MPH).

Added to this is the ability to interface to a standard paddle-wheel log transducer and calculate the vessel’s speed and the trip distance travelled (log).

The final ability of interfacing to a standard temperature transducer, to calculate the current water temperature, completes the picture of this powerful, all-in-one system.

Simply install the Actisense Active DST Module (and the associated transducers if not already fitted) and connect it to your NMEA 0183 network – normally through an NMEA Multiplexer (NDC-4) or an NMEA Buffer (NBF-2) – and all the NMEA data will be instantly available to any NMEA devices that require it.

Using the Actisense RS485 to RS232 Adapter cable and free software available (on this website when necessary), the NMEA Active DST Module software may be updated as many times as required with the very latest software enhancements, or even user defined software.

NBF-3 NMEA Buffer

What are the NBF-3 mounting options?

A DIN Rail mounting kit is available to order from Actisense. The kit is not supplied with the NBF-3-BAS. The kit is suitable for use with top hat rail, type EN 50 022 or G section rail, type EN 50 035.

The kit can be ordered using part number: DIN-KIT-1.

The NBF-3 can also be mounted on the bulkhead. Four M4 stainless steel pan-head screws are provided with the NBF-3 for mounting to the bulkhead.

Can I connect more than one NMEA Listener device to a single NBF-3 Talker port?

Yes, but there are several things to consider; firstly, each NBF-3 Talker port can drive up to 20mA. Check the sum of currents for all the NMEA Listener devices does not exceed 20mA. As a guide, the NMEA 0183 specification states that an NMEA 0183 Listener port should not draw more than 2mA, but some do require more.

Also, each Talker port is fully isolated; however the NBF-3 cannot provide isolation between the multiple Listener devices connected to a single Talker port. Connecting more than one NMEA Listener device is only recommended when all devices are known to have isolated inputs.

The total cable length and cable quality will also affect the number of devices that can be connected.

What is the NBF-3 power output for?

When connecting an NMEA Talker device to the NBF-3 Listener port, it is possible to also power the NMEA Talker device from the NBF-3. This means only a single cable need be run between the NMEA Talker device and the NBF-3, reducing installation time and cost. The NBF-3 ‘Power Output’connection has a self-resettable fuse providing up to 500mA to the NMEA Talker device at the voltage supplied to the NBF-3. Please refer to the specifications in the User Manual for more detail.

Can I use the NBF-3 with data that is not NMEA 0183?

Yes, the NBF-3 will generate an identical copy of the electrical signal it receives on its input port to each of its output ports. The electrical signal must use RS422, RS485 or RS232 voltage levels for its ‘High’ and ‘Low’ data levels.

As the NBF-3 only ‘sees’ the electrical signals, the data protocol used is not relevant and no protocol validation of the data is performed. Each output will be an identical copy of the input data regardless of the data protocol. The output voltage levels are amplified to RS422/RS485 levels when a differential input device is connected and and to voltage levels compatible with RS232 when a single-ended device is connected.

What if my NMEA Listener does not have an isolated input or uses ground for the negative data connection?

The NMEA 0183 specification, from version 2 (1996) onwards, requires a device’s Listener port to be isolated. Some NMEA 0183 devices however choose instead to follow version 1 of the specification which allowed for non-isolated inputs to be used.

The NBF-3 Talker/Output ports are all isolated so that an NMEA Listener (or other device) without an isolated input can be safely connected with no fear of ground-loop damage. Isolation is between every NBF-3 connection; power, Listener/Input port and all Talker/Output ports.

Does the NBF-3 need external power?

Yes, the NBF-3 requires a supply between 10 to 35V DC and will use a maximum of 100mA at 12V DC (when all outputs are fully loaded with 100?). This does not include the current draw of the NBF-3 ‘Power Output’ that can be used to power an NMEA Talker device up to an additional 500mA.

Is the NBF-3 a direct replacement for the NBF-2?

The NBF-3 is a replacement for the NBF-2. The NBF-3 has the same functionality as the NBF-2 with the addition of a fused power output for powering the NMEA Talker device (that supplies the NBF-3 with data). The new case design allows for quicker and easier connections whilst keeping the electronics fully protected. The NBF-2 will be retired from production at the end of 2013.

What are the NMEA 0183 Listener and Talker Designations?

The NMEA have updated the NMEA 0183 specification to ensure a consistent naming convention is used for labelling ports. The designation follows the same rules as used for Rx and Tx labelling but uses the descriptions’ Talker’ and ‘Listener’ instead. The input/receiving (Rx) port on a device will be labelled as a ‘Listener’ port. The output/transmitting (Tx) port on a device will be labelled as a ‘Talker’ port. When a port is labelled ‘Listener’ it is an input and when it is labelled ‘Talker’ it is an output.

Can I configure the NGW-1?

NMEA Reader contains all the currently available configuration options for the NGW-1.

In the majority of cases, configuration of an NGW-1 is not required as it communicates at the standard 4800 baud rate for NMEA 0183 devices (38400 for the AIS firmware) by default. All available conversions are enabled by default so the only conversion related configuration option is to reduce the number of conversions carried out by the NGW-1. Checking extra boxes in the PGN enable lists in NMEA Reader that weren’t initially checked will have no effect.

All available conversions being enabled on the NGW-1 should not cause conflicts as NMEA 0183 devices are usually good at recognising data that they don’t require and ignoring it. NMEA 2000 is also very good at handling data.

For full instructions on how to use NMEA Reader, please refer to the “NMEA Reader & EBL Reader User Manual Issue 1.00.pdf”. In the manual it shows the hardware configuration option as a window, however with the latest edition of NMEA Reader it is a tab that can be selected at the bottom left side of the NMEA Reader window.

As a quick description: Using NMEA Reader, you can choose which PGN’s are received (Rx) or transmitted (Tx) by the NGW-1. For example, turning off PGN 127251 from the “Rx PGN Enable List” will stop all ROT sentences appearing on the NMEA 0183 output of the NGW. However, turning off PGN 128267 from the “Rx PGN Enable List” will stop both DPT and DBT sentences appearing on the NMEA 0183 side of the NGW. There is currently no way of choosing DPT or DBT, you can only get or stop both.

The “Tx PGN Enable List” works in a similar way, DBT and DPT are used to generate PGN 128267 you cannot choose data from one sentences and not the other. Please refer to the NGW-1 Conversion List document to fully understand the relationship between the NMEA 2000 PGN and the NMEA 0183 Sentences.

Only the USB variant of the NGW-1 is capable of baud rates of 115200 Baud and above. Changing the Baud rate of non USB variants to 115200 Baud or above will prevent the NGW-1 from communicating and will require assistance from Actisense tech support.

See question number 4 for details on how to connect your NGW-1 to a PC.

Can I connect multiple Listeners to an NGW-1?

The NGW-1 talker port can drive up to 20mA. This means that potentially up to 10 NMEA Listeners can be connected to the NGW-1 output. Check the input currents of each Listener to see how many can be connected together.

Note that many NMEA Listeners do not provide isolation on their inputs. Connecting these together can cause ground loops and thus damage to the Listener ports of these devices. For safe connection of multiple Listeners our NBF-3 NMEA Buffer is recommended.

Can I connect multiple Talkers to an NGW-1?

No, it is not possible to connect multiple Talkers to a NGW-1’s Listener port. (This is in accordance with the NMEA 0183 specification). You can use an NMEA multiplexer like the NDC-4 to combine multiple NMEA 0183 streams together to put into the NGW-1. Alternatively, using more than one NGW-1 is the recommended option.

Note: three NGW-1’s cost approximately the same as one NDC-4 plus one NGW-1.

Can I connect a different Listener and Talker to the NGW-1’s NMEA 0183 port?

It is possible to connect an NMEA Listener to the NGW-1 Talker port and a different NMEA Talker to the NGW-1 Listener port. Note that both NMEA 0183 devices connected to the NGW-1’s NMEA 0183 port must have the same baud rate set.

Is there isolation between all the ports?

What versions of NMEA 0183 are supported?

The NGW-1 supports all versions of NMEA 0183. Devices that use RS232 or RS422 voltage levels are accepted and connections that use ground or differential connections are suitable. The NGW-1 automatically adapts to the electrical requirements of the connected devices.

How do I connect my ISO-Drive variant NGW-1 to a PC?

When connecting an NGW-1 with an ISO-Drive to a PC there are three options:

Wire a D-type 9-pin connector and cable to your NGW-1’s NMEA 0183 (ISO-Drive) port – you can connect that directly to the NGW-1 cable terminals inside the case if that is more convenient. Plug that cable in to a standard RS232 port, or a “USB to Serial” adapter cable if your computer does not have an RS232 port. Please refer to “Figure 2” on page 7 of the NGW-1 User Manual.

You might want to consider theActisense DB9-F and USB-1 products if do not have cables already.

For a quick and easy connection, use theActisense USG-1 for direct wiring to the NGW-1’s cable terminals whilst keeping your PC safe with 1500 volts of isolation. You can use the USG-1 as a safe way to connect any NMEA 0183 signal to your PC so it is ideal as an “NMEA 0183 diagnostic tool” when used with our freely available NMEA Reader software.

If the NGW-1 is not connected to an NMEA 2000 network, an alternative NGW-1 power source is required: 12/24 volt power can be connected directly to the “Net S” and “Net C” terminals inside the NGW-1-ISO case.

Can I change/update the firmware in my NGW-1?

Yes you can. To change/update firmware, please follow these instructions:

Locate and download the required ActiPatch from the Actisense website. For example, if you have an NGW-1-STNG and you wish to enable AIS conversions, you will need “NGW-1-STNG-AIS v2.420 ActiPatch Setup.exe”

To connect your NGW-1 (ISO Variants) to a PC (to update its firmware) you have the following options:

Wire a D-type 9-pin connector to your NGW-1’s NMEA 0183 port (you can connect that directly to the NGW-1 terminals inside the case if that is more convenient), and then connect to a standard “USB to Serial” adapter cable if your computer does not have an RS232 port on it. Please refer to the NGW-1 User Manual for wiring instructions.

‘D-type 9-pin’ connectors are available from an Actisense dealer. USB to serial converters can be purchased from Amazon

For a quick and easy connection, use our Actisense USG-2 product for direct wiring to the NGW-1’s terminals whilst keeping your PC safe with 1500 volts of isolation.You can use the USG-2 as a safe way to connect any NMEA 0183 signal to your PC so it is great as an NMEA 0183 diagnostic tool when used with our freely available NMEA Reader software

Note that with the ISO variants of the NGW-1, power needs to be present on the NMEA 2000/SeaTalkNG side of the NGW-1 for the PC connection to be powered and active. The USB variants are powered once the latest USB drivers have been successfully downloaded and installed.

With the NGW-1 connected to your PC, select the correct COM port for your NGW-1 from the drop down menu in the Actipatch you just downloaded.

Click on the ‘Program’ button when it goes green and you will see the progress bar indicating the installation of the firmware to your NGW-1.

When the installation is completed successfully, the ‘Patch ID’ box and ‘Device ID’ box will contain identical information.

What conversions are supported by the NGW-1?

The NGW-1 Conversion Lists are available on the download page – there is one list for the standard firmware variants (NGW-1-ISO, NGW-1-USB and NGW-1-STNG) and one list for the AIS firmware variants (NGW-1-

ISO-AIS and NGW-1-USB-AIS). Each Conversion List details which conversions are supported by the specified NGW-1 firmware version. Updating the NGW-1 between the standard firmware and AIS firmware (using the ActiPatch program) switches between the two Conversion Lists. The latest NGW-1 firmware can be found on the firmware page.

New conversions are being developed – Actisense welcomes suggestions and requests for future updates.

How is the NGW-1 Powered?

All ISO-Drive variants (NGW-1-ISO, NGW-1-ISO-AIS and NGW-1-STNG) are completely powered from the NMEA 2000 network and have an NMEA 2000 LEN of 1 (50 mA or less). Once connected to a powered and terminated NMEA 2000 network, the NGW-1-ISO LEDs will flash.

All USB variants (NGW-1-USB and NGW-1-USB-AIS) takes most of their power from the USB connection and also have an NMEA 2000 LEN of 1 (50 mA or less). The LEDs will not flash until the USB drivers have been successfully installed (allowing the OS to enable USB power).

All ISO-Drive variants (NGW-1-ISO, NGW-1-ISO-AIS and NGW-1-STNG) have stripped and tinned wires at the end of a high quality 1.5 metre cable to accommodate varying installation requirements to an NMEA Talker and/or NMEA Listener.

All USB variants (NGW-1-USB and NGW-1-USB-AIS) have a 1.5 metre standard USB cable with a USB A plug on the end for easy connection to a computer or USB hub.

The NGW-1-ISO is the standard option applicable to the majority of customers. The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-ISO-AIS is an NGW-1-ISO pre-configured for use with an AIS device. The NGW-1-AIS Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-USB is the option typically used with PC software that only understands NMEA 0183 (i.e. it is not compatible with the Actisense NGT-1). The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-USB-AIS is an NGW-1-USB pre-configured for use with PC software that only understands NMEA 0183 and needs or supplies AIS information. The NGW-1-AIS Conversion List on the download page details which conversions are supported (and those that are not).

The NGW-1-STNG is the Raymarine SeaTalkNG option: The kit includes an NGW-1-ISO and a SeaTalkNG to NMEA 2000 adapter cable (STNG-A06045) allowing the NGW-1 to be connected directly to the Raymarine SeaTalkNG network – providing seamless integration with Raymarine products. The NGW-1 Conversion List on the download page details which conversions are supported (and those that are not).

As of April 2015, a SeaTalkNG to NMEA 2000 adapter cable (STNG-A06045) can be purchased with an NGW-1-ISO, NGW-1-ISO-AIS, NGW-1-USB or NGW-1-USB-AIS to allow direct connection toa Raymarine SeaTalkNG network

What wire gauge should I use to connect my engine sensors?

Can I custom configure the EMU-1?

The current version of the Toolkit (that contains the EMU Configuration Tool) does not offer this as a feature.

There is a beta option of Toolkit available with a ‘Custom Gauge Manager’ option to enter manual calibration readings for various gauges and senders. This requires a technician to take readings from the gauges using a multi-meter and then enter this corresponding data into the configuration program. This will allow for any analogue gauge to be catered for if the installer fills in the voltmeter readings vs. observed parameter on the existing gauge.

However, Actisense is actively analysing gauges and senders from all manufacturers to help create a comprehensive library of easy to select gauge options, with the end goal of making this manual configuration option unnecessary.

What parameters will the future Software or Configuration updates support?
Actisense welcomes any suggestions for new EMU-1 features and gauge compatibilities that will be added to the ‘wish list’. Current items on the EMU-1 ‘wish list’ are:

Is the engine hour log stored in non-volatile memory?

Yes, from EMU-1 firmware v0.041 (and onwards) the Engine Operating hour log is stored in non-volatile memory and restored at the start of every session. Note that in EMU-1 firmware v0.022 (and below) the Engine Operating hour log would reset on a power cycle as it was not stored in non-volatile memory.

What baud rate should my NGT-1 be set to?

The default NGT-1 baud rate from firmware version 2.600 is 230,400.

NGT-1’s with earlier firmware use a baud rate of 115200, which is ideal for use on an NMEA 2000 network with a peak bus load below 50%. NMEA Reader displays the current “NMEA 2000 Bus Load” to help the user understand if the peak bus load is above 50%, and if so allow the user to change the NGT-1 baud rate to 230400 baud rate.

What is the temperature range an EMU-1 gauge input can be used to measure?

This temperature range is dependent on what gauge is defined by EMU Configuration Tool for that input. An EMU-1 “Gauge” input set to measure “Temperature” is capable of measuring temperatures outside of the defined gauge range. For example, selecting a “40 to 120 degrees C” gauge can actually allow the EMU-1 to report temperatures all the way down to below 0 degrees C and above 140 degrees C. This is because the EMU-1 calibration curve for the sender/gauge has been extended beyond the gauge display range. However, the accuracy of the calibration curve outside of the normal gauge display range is usually compromised.

Can I connect an EMU-1 to Dual Station senders?

Yes, the EMU-1 is compatible with both single and dual station senders.

A dual station sender must always have two gauges connected to it: the EMU-1 cannot replace one or both of those gauges. If it is required to remove one or both gauges, the dual station sender will need to be replaced with a single station sender.

How do I update the firmware in my EMU-1?

Firstly, ensure that an Actisense NGT-1 (with firmware v2.210 or above) is connected to both your PC and the same NMEA 2000 network as the EMU-1 to be updated. Secondly, ensure that any other software program (such as NMEA Reader) has not opened the NGT-1’s COM port.

Toolkit is the simple tool that contains the latest EMU-1 firmware. Run Toolkit and select the NGT-1 COM port from the “Comms” menu. The selected NGT-1 COM port will be remembered for all future sessions but it can be changed at any time if required. Select the EMU-1 to be updated from the “Serial/CAN Device List”:

Click on the “Upgrade Firmware” button in the Toolkit ribbon menu to start the reprogramming process, followed by the “Program” button in the pop-up window.

The blue “Power” LED on the EMU-1 should now be flashing faster (5 times per second) to indicate that the EMU-1 is in Bootloader mode. The “Tx” and “Rx” LED’s on the EMU-1 should be flashing very fast indicating the transfer of firmware information.

What are the EMU-1 mounting options?

The EMU-1 comes complete with four stainless steel bulkhead mounting screws as the standard mounting method. Alternatively, the EMU-1 can be used with an optional DIN rail mounting kit: order part number DIN-KIT-1 which is suitable for use with top hat rail, type EN 50 022 or G section rail, type EN 50 035.

Why do I need an Actisense NGT-1 NMEA 2000 PC Interface on the network?

As the EMU Configuration Tool software program runs on a Windows PC it requires an interface to the NMEA 2000 network in order to configure and update the firmware of an EMU-1. This NMEA 2000 PC Interface is created by an Actisense NGT-1, making it a necessary requirement when installing or reconfiguring an EMU-1.

It is not necessary to keep the Actisense NGT-1connected to the NMEA 2000 network permanently; once the EMU-1 is configured it can be removed. However, having an Actisense NGT-1 always available to help diagnose issues with any NMEA 2000 device (from any manufacturer) will prove very helpful, and is a solid reason for keeping it on-board full-time.

Does the EMU-1 come with a cable harness?

Can I request what I would like the EMU-1 to support?

The Actisense team are actively requesting customer feedback on future EMU-1 features and functionality. If you would like to make a request, please contact Actisense Technical Support. Your requests will be added to the EMU-1 ‘Wish List’ that is used to prioritise new features and functionality

The parameter / gauge type is specified for each active “Gauge” input.

The alarm level and direction is specified for each active “Alarm” input.

The tacho PPR ratio is specified for each active “Tacho” input.

The configuration settings are sent to the EMU-1 by pressing “Send to EMU” button.

The EMU Configuration Tool User Manual details how to perform all of the configuration operations necessary to customise the EMU-1 to an individual installation. As the EMU Configuration Tool will be updated regularly, please ensure that the latest version is being used.

What engines is the EMU-1 compatible with?

Actisense is actively building up a database of what senders/gauges are to be found on which engines. However, that will take some time to compile as there are a large number of sender/gauge permutations even within a single engine model’s lifetime (as manufacturing methods change year on year). One of the primary inputs to this database is from EMU-1 customers and a future configuration option will make it easier for customers to send us the details of a working setup.

The current EMU-1 configuration requires the user to understand the specific manufacturer and type of each sender/gauge connected to the EMU-1 so they can select the matching option in the EMU Configuration Tool.

Can the EMU-1 be connected in parallel to existing gauges?

The EMU-1 can be connected in parallel to existing gauges or as a replacement for some or all of the gauges. The EMU-1 automatically detects whether a gauge is present or not and configures itself to provide a current feed to the sender where required.

What gauges are compatible with the EMU-1

What are the “Tacho” inputs for?

“Tacho” inputs are designed to be connected to existing Tacho signals from either the Alternator (“W”, ”R” or “AC”) terminal, an inductive Tach sender, an ignition coil or – a hall-effect Tacho sender. The EMU Configuration Tool allows the user to define “Ratio” or the number of “Pulses Per Revolution” that the selected Tacho signal will generate for each “Tacho” input. This ratio is usually referred to as the Pulses Per Revolution (PPR) and is normally supplied in the engine manual.

For an Alternator “W”, ”R” or “AC” terminal connection it can be calculated from:

For an inductive Tach sender it is derived from the number of teeth on the flywheel:

For an ignition coil it can normally be calculated from:

The engine manufacturer will usually supply this ratio so it should not need to be calculated.

The EMU-1 has the ability to automatically adjust to the input Tacho signal so the sender type does not need to be configured. However, currently only Alternator (“W”, ”R” or “AC”) and inductive Tach sender signals are sensed correctly by the EMU-1. If you wish to use an ignition coil signal with an EMU-1 please contact Actisense Technical Support so your request a can be processed.

What are the “Alarm” inputs for?

“Alarm” inputs are designed to be connected to existing (voltage level) alarm type switches, (e.g. an over temperature switch). The EMU Configuration Tool allows the user to define the trigger voltage and trigger direction (positive: from LOW to HIGH or negative: HIGH to LOW) for each “Alarm” input. The user configures this as: Trigger the alarm if the input voltage goes “Above” or “Below” the set trigger level.

Please check that you have the latest version of the EMU Configuration Tool in order to have the latest supported alarm list.

What are the “Gauge” inputs for?

“Gauge” inputs are designed to be connected to existing (resistive type) engine senders, either with or without the engine gauge connected. In the case where no gauge is connected the EMU-1 automatically provides a current feed to the sender.

The EMU Configuration Tool allows the user to select the matching sender/gauge type from a defined list for each “Gauge” input. Ideally, please check regularly (once per month) that you have the latest version of the EMU Configuration Tool in order to have the latest supported gauge list.

If you have a gauge which is not supported, please contact Actisense Technical Support so your “new gauge” addition request a can be processed. The Actisense team will be updating the EMU Configuration Tool to support more gauge types based on customer feedback and requirements.

What are the power requirements of the EMU-1?

The EMU-1 can operate between 9 and 35 VDC and will typically use 25mA at 12 VDC.

If the engine gauges are to remain in-circuit, the EMU-1 must be powered from exactly the same power supply as the gauges otherwise the EMU-1 measurements will not being accurate. The EMU-1 gauge ground and the EMU-1 power ground must be common to prevent ground loops. Check that if the instrument gauge panel includes a reverse protection diode between the power supply and the actual gauge supply connection, the EMU-1 is correctly powered from the gauge supply connection.

Which devices can receive engine data from the EMU-1?

The EMU-1 is compatible with all certified NMEA 2000® devices that receive and display the NMEA 2000 PGNs that the EMU-1 outputs. Please cross-reference the EMU-1 NMEA 2000 PGN list (in the User Manual and in the Which NMEA 2000 PGNs are supported FAQ) with the receive PGN list of the NMEA 2000 monitoring device (e.g. MFD or chartplotter).

Any Raymarine SeaTalkNG or Simrad SimNet device that can receive and display the NMEA 2000 PGNs that the EMU-1 outputs will also be compatible, however a suitable network adapter cable will be required.

NGT-1 NMEA 2000 to PC Interface

Can the NGT-1 configure other manufacturer’s devices?

The NMEA 2000 standard has standard methods for changing configuration names and other parameters within their devices. The NGT-1 can alter these in conjunction with the NMEA reader software. Some manufacturers may block these change requests, but most support it.

What baud rate can the NGT-1 work up to?

The NMEA Software Range

SDK Software Development Kit

Can I use the SDK with Mac or Linux systems?

The ActisenseComms SDK is specifically for Windows systems and is the quickest and easiest way to access the NGT-1 (and NGW-1). For MAC and Linux based systems, we do have an alternative solution available – please contact the Actisense Support Team, for more information. The ActisenseComms SDK is a great place to start, with examples and a full user manual to aid the design process. This can form an invaluable foundation that will benefit all who later wish to follow a more complicated MAC or Linux developmental route.

What are the ActisenseComms Wrappers for?

When using a programming language other than C/C++ the ActisenseComms dll cannot be directly accessed, so a Wrapper is required to allow access. We currently provide Wrappers for C# and VB.net. For other programming languages a Wrapper will need to be written in the language being utilised.

What is provided in the ActisenseComms SDK package?

The SDK contains:

All the files required to develop a software interface to a compatible Actisense product (NGT-1 and NGW-1) using C/C++ as a programming language.

A Visual Studio ‘Demo’ project including full source code that is fully debuggable. This includes examples of how to use each and every function that makes up the ActisenseComms API and should be the ‘first point of call’ for every developer.

A full user manual that starts by explaining how to use each ActisenseComms API function and ends with a “How to…” section built up from the answers to previous developer’s questions.

How can I get my software NMEA 2000 approved?

The Actisense NGT-1 will gain Third Party Gateway (TPG) certification once the NMEA working group has finalised the TPG requirements. When the NMEA 2000® ‘Third Party Gateway’ certification becomes available, for a small fee Actisense will be able to test if your software (working with an NGT-1) meets the official NMEA 2000 requirements. Once your software has passed these tests, you will be able to state that your software is “NMEA 2000 approved when used with the Actisense NGT-1”.

How can using Actisense NMEA Reader help me? (NMEA Reader)

Actisense NMEA Reader is a very useful resource that uses the ActisenseComms API to break down and display the individual fields of each NMEA 2000® message. The breakdown of the messages is great for debugging your own software and for better understanding the NMEA 2000 bus and its multitude of messages. NMEA Reader can also be used to break down and display the individual fields of NMEA 0183 messages. Visit the NMEA Reader page, for full details.

What costs can a developer save? (Web-links)

The Actisense NGT-1 takes care of the vast majority of the NMEA 2000® protocol so the developer does not need to spend the many thousands (of $) on the complete NMEA 2000 documentation and many hundreds of hours implementing it. Instead the only additional resource you will need to create an NMEA 2000 capable software program is the NMEA 2000 “Appendix B”, available from the NMEA. Visit this link for NMEA 2000 Appendix B costs: https://www.nmea.org/store/index.asp?show=pdet&pid=325&cid=7. Visit this link for information about NMEA Membership: https://www.nmea.org/store/index.asp?show=cprd&cid=2.

Who is already using the ActisenseComms SDK? (“Software Compatibility List”)

We are already helping a number of companies to create an interface to the NGT-1 (and NMEA 2000), please visit our “Software Compatibility List” page, for full details. If you would like your software to be included on our compatibility list, please contact the Actisense Support Team.

How can I gain access to the ActisenseComms SDK? (Actisense Support Team)

The ActisenseComms SDK and its ‘Wrappers’ are available to download without charge, please contact the Actisense Support Team, to discuss your project requirements and obtain the passwords necessary to access the SDK files. The files are available on the Downloads page.

Retired

USG-1 USB to NMEA

How many NMEA 0183 devices can the USG-1’s output drive?

Whilst the USG-1’s output is capable of driving up to 8 NMEA 0183 instruments, to maintain the galvanic isolation between each of the NMEA devices, it is recommended to connect only one NMEA device.

If all the NMEA 0183 devices connected to the NMEA output are proven to have a correct NMEA 0183 opto-isolated input, then it is possible to connect the USG-1 output to multiple NMEA devices and still maintain galvanic isolation. However, this is the only condition where multiple NMEA 0183 devices is recommended.

When connecting multiple NMEA devices, the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.

If bi-directional communications are required, then only one NMEA 0183 device can be connected to the USG-1.

Why would I want or need an isolated USB to NMEA 0183 gateways?

When software running on a PC needs access to NMEA 0183 data from a particular device, or alternatively, may need to send NMEA 0183 data, a communication port needs to be created.

The Actisense USB to Serial Gateway was developed to solve 3 fundamental problems with interfacing the marine industry NMEA 0183 communications standard to a PC:

A) Ground loops. When the PC and the NMEA 0183 system have different ground potentials (or are totally different ground altogether), data can become corrupted and permanent damage can occur (to the PC and NMEA device).

C) The PC has no serial port. Most modern PCs do not come with serial ports, most are now USB.
Solution for problem A – Ground loops

The primary problem encountered when using a standard USB to serial converter (or a standard RS232 port) is that the ground of the PC is then shared with the NMEA 0183 system ground.

PCs are often powered from a mains inverter, generator set or direct from mains supply when in dock, whereas the marine electronics are normally connected to the current battery set.

This means that when you connect the two systems together, you are joining two different power systems. This can result in no visible problems at first, but more often it results in one of three consequences:

Data corruption – the data becomes garbled as the electrical data signal now floats on a noisy ground current flowing between two systems.

The PC crashes intermittently as ground currents flow across its sensitive electronic circuitry. This can cause permanent damage.

In the case of large ground loop faults, some components can melt / catch fire / fuses blow or earth leakage devices trip.

The USG-1 solves all these problems by providing a safe, opto-isolated barrier between the two systems. Because the signal travels across this barrier as light, the signals do not share the same ground, and safety is assured as no current can flow between the two power systems. In addition, a built-in power isolator completes the isolation.

Solution for problem B – Different standards

PC serial or “COM” ports use the RS232 standard. This uses a ground and a receive pin to get data from a connected system. Data is sent as voltages referenced to ground on a single transmit line. This type of drive is known as “single-ended”.

In contrast, NMEA 0183 systems use a “differential” system, where a “Positive” data line and a “Negative” data line move in opposition to each other.

Many installations without isolated outputs have been seen where the negative data line on a differential drive system has been connected to the ground of the PC. If you’re lucky, this may work, but if not, you will either simply get no data, or at worst, damage your equipment.

The USG-1 solves this by using ingenious circuitry unique to Actisense in both it’s “Listener” (receiver) circuit and its ISO-Drive “Talker” (transmitter) circuit. These circuits are compatible with both RS232 and NMEA 0183.

Solution for problem C – PC has no serial port.

Many laptop and desktop PCs do not come equipped with RS232 type serial ports any more. The USG-1 creates a marine standard NMEA 0183 port from any PC USB port.

This port appears on the PC system as a regular “COM” port, and so can be used with all standard navigation and display software. This allows a connection to be up and running in minutes.

RS485-1 RS485 to RS232

Why would I want or need an RS485 TO RS232 adapter cable?

The RS485 to RS232 adapter has been primarily designed to be used with the Actisense Active DST Module and Active Transducer, and future Actisense NMEA 0183 sensors.

It enables these Actisense product’s Flash to be updated with the latest software, whenever it becomes available on this website (please refer to the Software section for latest details).

This adapter cable allows easy, safe and low-cost connection of an Actisense NMEA product to a laptop or PC, by matching a standard RS232 D-type 9-pin serial port to an NMEA 0183 type marine bus link.

It needs no external power supply as the interface takes all the power it needs from the computer port. Once the cable is wired to the NMEA interface and the connector is plugged into the computer, the Actisense product will be ready to be reprogrammed.

This adapter contains a full RS485 (automatic) bi-directional interface using just 2 wires. With built in protection against electrostatic discharge (up to 3000 volts), this does not provide the complete protection of the Opto-isolator product, as the ground connection is still common between input and output. However, it will protect a computer against most common noise spikes present on a boats wiring network.

Alternative uses for this adapter cable are possible, although only in 2-wire systems that also require the automatic switchover between receive and transmit modes.

For a more compatible 4-wire adapter between RS422 / RS485 and RS232, with the added benefit of full Galvanic Opto-isolation, please view the NMEA Opto-isolator adapter.

PC-OPTO-3 NMEA to RS232 Opto-isolator

Why would I want or need an NMEA Opto-isolator adaptor cable?

Simply put, to protect your computer investment – if the serial communications port on a laptop is damaged, it is normally a very expensive repair that could require replacement of the entire motherboard. This cable allows easy, safe and low-cost connection of an NMEA 0183 system (or any other compatible RS422 / RS485 system) to a laptop or PC, by matching a standard RS232 D-type 9-pin serial port to an NMEA 0183 type marine bus link.

Potentially damaging voltage or current spikes can be present in the electrically noisy environment of the vessels wiring network – alternators, motors etc. can induce or conduct very large voltage and current spikes into the vessels power cables; computer ports (RS232, USB etc.) are designed to handle low voltage and low current signals only and are easily to damage in the marine environment.

This adapter cable needs no external power supply as the interface takes all its power from the computer port. Once the cable is wired to the NMEA 0183 network, and the connector plugged into the computer, the data will be available via its serial communications port.

If you require more flexibility for a RS232 / computer source to add its own NMEA data to the NMEA network, the Actisense NMEA Multiplexer (NDC-4) will fulfill most if not all requirements.

Why would I want or need an NMEA opto-isolator adapter cable?

Simply put, to protect your computer investment – if the serial communications port on a laptop is damaged, it is normally a very expensive repair that could require replacement of the entire motherboard. This cable allows easy, safe and low-cost connection of an NMEA 0183 system (or any other compatible RS422 / RS485 system) to a laptop or PC, by matching a standard RS232 D-type 9-pin serial port to an NMEA 0183 type marine bus link.

Potentially damaging voltage or current spikes can be present in the electrically noisy environment of the vessels wiring network – alternators, motors etc. can induce or conduct very large voltage and current spikes into the vessels power cables; computer ports (RS232, USB etc.) are designed to handle low voltage and low current signals only and are easily to damage in the marine environment.

This adapter cable needs no external power supply as the interface takes all its power from the computer port. Once the cable is wired to the NMEA 0183 network, and the connector plugged into the computer, the data will be available via its serial communications port.

The computer, radar or chart plotter will then be capable of reading any transmitted NMEA 0183 sentences, for display by any standard NMEA 0183 display software, such as a chart plotter program or the Actisense NMEA Multi-display program, and will also able to send NMEA 0183 sentences back to the attached instrument.

If however, you require more flexibility for a RS232 / computer source to add its own NMEA data to the NMEA network, the Actisense NMEA Multiplexer (NDC-4) will fulfill most if not all requirements.

This product can combine, or multiplex up to 5 NMEA 0183 instrument outputs together, and in addition, multiplex in the NMEA data from a computer via its dedicated RS232 port (standard computer serial port).

Can I use the NMEA Opto-isolator for other non-NMEA uses?

Yes. The NMEA Opto-isolator adapter has been specifically designed to work as an isolator for the NMEA system. However, it can also be used in most systems that use the RS422 or RS485 (4-wire) connection protocols.

The Opto-isolated adapter cable utilises a full Galvanic Opto-isolated input circuit to protect the RS232 / PC’s receiver and a TransZorb diode to protect the RS232 / PC’s transmitter.

As an example of alternative uses, by using two adapters at each end of a cable (back-to-back), the normal maximum RS232 cable length of 20 metres can be extended up to and beyond 100 metres.

In the RS232 / PC receive direction, it provides complete isolation of expensive RS232 / computer hardware when connecting to an NMEA 0183 bus link that may have picked up potentially hazardous voltages around the electrically noisy environment of a boat.

In the RS232 / PC transmit direction, a TransZorb diode provides a high level of static spike protection, but does not offer the complete protection of an opto-isolator and so is only recommended for connection to equipment with Opto-isolated inputs.

OPTO-2 NMEA to RS232 Opto-isolator

Can I use the NMEA Opto-isolator for other non-NMEA uses?

Yes. The NMEA Opto-isolator adapter has been specifically designed to work as an isolator for the NMEA system. However, it can also be used in most systems that use the RS422 or RS485 (4-wire) connection protocols.

The Opto-isolated adapter cable utilises a full Galvanic Opto-isolated input circuit to protect the RS232 / PC’s receiver and a TransZorb diode to protect the RS232 / PC’s transmitter.

As an example of alternative uses, by using two adapters at each end of a cable (back-to-back), the normal maximum RS232 cable length of 20 metres can be extended up to and beyond 100 metres. The longest ‘cable extender’ length currently acheived by a customer is 200 metres In the RS232 / PC receive direction, it provides complete isolation of expensive RS232 / computer hardware when connecting to an NMEA 0183 bus link that may have picked up potentially hazardous voltages around the electrically noisy environment of a boat.

In the RS232 / PC transmit direction, a TransZorb diode provides a high level of static spike protection, but does not offer the complete protection of an Opto-isolator and so is only recommended for connection to equipment with Opto-isolated inputs.

OPTO-1 NMEA to RS232 Opto-isolator

Can I use the NMEA Opto-isolator for other non-NMEA uses?

Yes. The NMEA Opto-isolator adapter has been specifically designed to work as an isolator for the NMEA system. However, it can also be used in most systems that use the RS422 or RS485 (4-wire) connection protocols.

As an example of alternative uses, by using two adapters at each end of a cable (back-to-back), the normal maximum RS232 cable length of 20 metres can be extended up to and beyond 100 metres. The longest ‘cable extender’ length currently acheived by a customer is 200 metres In the RS232 / PC receive direction, it provides complete isolation of expensive RS232 / computer hardware when connecting to an NMEA 0183 bus link that may have picked up potentially hazardous voltages around the electrically noisy environment of a boat.

In the RS232 / PC transmit direction, a TransZorb diode provides a high level of static spike protection, but does not offer the complete protection of an Opto-isolator and so is only recommended for connection to equipment with Opto-isolated inputs.

Why would I want or need an NMEA opto-isolator adapter cable?

Simply put, to protect your computer investment – if the serial communications port on a laptop is damaged, it is normally a very expensive repair that could require replacement of the entire motherboard. This cable allows easy, safe and low-cost connection of an NMEA 0183 system (or any other compatible RS422 / RS485 system) to a laptop or PC, by matching a standard RS232 D-type 9-pin serial port to an NMEA 0183 type marine bus link.

Potentially damaging voltage or current spikes can be present in the electrically noisy environment of the vessels wiring network – alternators, motors etc. can induce or conduct very large voltage and current spikes into the vessels power cables; computer ports (RS232, USB etc.) are designed to handle low voltage and low current signals only and are easily to damage in the marine environment.

This adapter cable needs no external power supply as the interface takes all its power from the computer port. Once the cable is wired to the NMEA 0183 network, and the connector plugged into the computer, the data will be available via its serial communications port.

The computer, radar or chart plotter will then be capable of reading any transmitted NMEA 0183 sentences, for display by any standard NMEA 0183 display software, such as a chart plotter program or the Actisense NMEA Multi-display program, and will also able to send NMEA 0183 sentences back to the attached instrument.

If however, you require more flexibility for a RS232 / computer source to add its own NMEA data to the NMEA network, the Actisense NMEA Multiplexer (NDC-4) will fulfill most if not all requirements.

This product can combine, or multiplex up to 5 NMEA 0183 instrument outputs together, and in addition, multiplex in the NMEA data from a computer via its dedicated RS232 port (standard computer serial port).

NSW-1 NMEA Autoswitch

I do not have a serial port on my laptop computer. How can I connect the NMEA Autoswitch to it?

There is a simple solution, use an Actisense USB to Serial adapter cable (USB-1). This cable will convert a USB port on your laptop computer into a fully functional serial communications (RS232) port, allowing the NMEA Autoswitch RS232 output to be connected to a computers USB port.

Simple Plug’n’Play installation and operation makes this a perfect solution.

Can I use an NMEA Multiplexer with my NMEA Autoswitch?

Yes, is the simple answer. The NMEA Autoswitch has been specifically designed to work together with the NMEA Multiplexer / Combiner to create a complete NMEA system solution.

The normal NMEA system would have an Actisense NMEA Autoswitch connected to two (or more) GPS / Depth sounder units. The NMEA Autoswitch adds a special NMEA tag to the data that passes through it to help identify which of these GPS / Depth sounder units supplied the NMEA data.

The autoswitched NMEA output is connected to one of the NMEA Multiplexer’s inputs. In this way the highest priority device’s NMEA data is autoswitched into the complete NMEA system and the actual device supplying the NMEA data can be determined (and displayed if required and possible) to help the user.

Why would I want or need an NMEA Autoswitch?

The NMEA 0183 standard allows any suitably designed marine electronic device to share its gathered information with any other device on a vessel. Unfortunately, there is one very large drawback with this standard – only one device on a connected network can actually send data (a single ‘talker’ device), with multiple devices (determined by the current limit of the sending unit) listening to that data (multiple listeners).

Secondly, for systems that have multiple NMEA devices of an identical type (e.g. two GPS’s or two depth sounders), automatic selection of the highest priority device with valid data is normally a vital requirement. However, the NMEA 0183 standard has no method of automatically switching between different devices, so this requirement is usually fulfilled with a manual changeover switch: not a very good solution, but the only one available until now.

The Actisense NMEA Autoswitch solves both of these problems by allowing up to 4 input devices/talkers, connected through full galvanic opto-isolated inputs, to be analysed, and the NMEA data of the highest priority device automatically switched to the NMEA output.

NDC-3 NMEA Multiplexer

How do I give my GPS unit priority on the NMEA data Mulitplexer network?

The Actisense NDC-2 and NDC-3 have many useful features, among which is the ability to prioritise their input ports. The usefulness of this feature becomes apparent when the NMEA network is running over 50% loading/capacity (most setups). At this point a standard NMEA Multiplexer could start to delay the important information by an unacceptable amount and may even lose it altogether.

The Actisense NDC however, will always transfer the highest priority input’s NMEA sentences first, keeping the delay to the minimum possible. The remainder of the inputs will have their NMEA sentences transferred in turn, until all data is either transferred or no more time / bandwidth is available in the NMEA output.

For example, the most relied upon unit e.g. GPS, should be attached to input port 1 (the highest priority). It is possible to change the port priority order from within the Control Centre software if you do not want to manually reconnect the cables to the Actisense NDC. However, it may be simpler to the keep the port priority in a logical order (1 highest – 4 lowest).

The Actisense NDC-2 ‘Port Priority’ default is the same as the port number, i.e. port 1 is the highest priority and port 4 the lowest.

Can I use an NMEA Autoswitch with an NMEA Data Multiplexer?

Yes, is the simple answer. The Actisense NMEA Autoswitch has been specifically designed to work together with the NMEA Multiplexer / Combiner to create a complete NMEA system solution.

The normal NMEA system would have an Actisense Autoswitch connected to two (or more) GPS / Depth sounder units. The Autoswitch adds a special NMEA tag to the data that passes through it to help identify which of these GPS / Depth sounder units supplied the NMEA data.

The autoswitched NMEA output is connected to one of the NMEA Data Multiplexers inputs. In this way the highest priority device’s NMEA data is autoswitched into the complete NMEA system and the actual device supplying the NMEA data can be determined (and displayed if required and possible) to help the user.

Why would I want or need an NMEA Data Multiplexer?

The NMEA 0183 standard allows any suitably designed marine electronic device to share its gathered information with any other device on a vessel. Unfortunately, there is one very large drawback with this standard – only one device on a connected network can actually send data (a single ‘talker’ device), with multiple devices (determined by the current limit of the sending unit) listening to that data (multiple listeners).

If the vessel owner has an instrument that ideally requires the data output of two or more devices, for example a chart plotter, then the owner has no alternative but to settle on connecting only the most important device, usually the GPS.

What happens if the owner prefers the vessels gyro compass output to that of the GPS, or requires that the current depth be displayed on the plotted chart to help avoid the possible case of running the vessel aground on a shifting sand bank? The NMEA 0183 standard cannot supply an answer to those questions: “one transmitting / talking device only”.

The Actisense NMEA Data Multiplexer’s NDC-2 and NDC-3 can solve all these problems and more with their simple, easy and flexible designs.

NDC-2 NMEA Multiplayer

How do I give my GPS unit priority on the NMEA data Mulitplexer network?

The Actisense NDC-2 and NDC-3 have many useful features, among which is the ability to prioritise their input ports. The usefulness of this feature becomes apparent when the NMEA network is running over 50% loading/capacity (most setups). At this point a standard NMEA Multiplexer could start to delay the important information by an unacceptable amount and may even lose it altogether.

The Actisense NDC however, will always transfer the highest priority input’s NMEA sentences first, keeping the delay to the minimum possible. The remainder of the inputs will have their NMEA sentences transferred in turn, until all data is either transferred or no more time / bandwidth is available in the NMEA output.

For example, the most relied upon unit e.g. GPS, should be attached to input port 1 (the highest priority). It is possible to change the port priority order from within the Control Centre software if you do not want to manually reconnect the cables to the Actisense NDC. However, it may be simpler to the keep the port priority in a logical order (1 highest – 4 lowest).

The Actisense NDC-2 ‘Port Priority’ default is the same as the port number, i.e. port 1 is the highest priority and port 4 the lowest.

Can I use an NMEA Autoswitch with an NMEA Data Multiplexer?

Yes, is the simple answer. The Actisense NMEA Autoswitch has been specifically designed to work together with the NMEA Multiplexer / Combiner to create a complete NMEA system solution.

The normal NMEA system would have an Actisense Autoswitch connected to two (or more) GPS / Depth sounder units. The Autoswitch adds a special NMEA tag to the data that passes through it to help identify which of these GPS / Depth sounder units supplied the NMEA data.

The autoswitched NMEA output is connected to one of the NMEA Data Multiplexers inputs. In this way the highest priority device’s NMEA data is autoswitched into the complete NMEA system and the actual device supplying the NMEA data can be determined (and displayed if required and possible) to help the user.

Why would I want or need an NMEA Data Multiplexer?

The NMEA 0183 standard allows any suitably designed marine electronic device to share its gathered information with any other device on a vessel. Unfortunately, there is one very large drawback with this standard – only one device on a connected network can actually send data (a single ‘talker’ device), with multiple devices (determined by the current limit of the sending unit) listening to that data (multiple listeners).

If the vessel owner has an instrument that ideally requires the data output of two or more devices, for example a chart plotter, then the owner has no alternative but to settle on connecting only the most important device, usually the GPS.

What happens if the owner prefers the vessels gyro compass output to that of the GPS, or requires that the current depth be displayed on the plotted chart to help avoid the possible case of running the vessel aground on a shifting sand bank? The NMEA 0183 standard cannot supply an answer to those questions: “one transmitting / talking device only”.

The Actisense NMEA Data Multiplexer’s NDC-2 and NDC-3 can solve all these problems and more with their simple, easy and flexible designs.

NDC-1 NMEA Multiplexer

How can the NMEA data Multiplexer reduce the congestion on my NMEA network?

Some NMEA instruments output a large number of NMEA sentences every period (usually 1-3 seconds), some of which are of no use to the average boat owner and just clog up the NMEA network. GPS units are especially guilty of this and not all allow the user to reduce the number of unwanted sentences that are transmitted. Of those that do, the procedure can often be fiddly and time consuming.

The Actisense NDC-1 and NDC-2 can filter the incoming NMEA data to remove any sentences that are deemed unnecessary by the user. Each input port has its own ‘Inclusion List’ which it uses to stop any NMEA sentences that are not on the list from appearing on the combined NMEA output port. If you do not require the ability to filter out unwanted NMEA data, then please view the Actisense NDC-3.

Can I use an NMEA Autoswitch with my NMEA Data Multiplexer?

Yes, is the simple answer. The Actisense NMEA Autoswitch has been specifically designed to work together with the NMEA Multiplexer / Combiner to create a complete NMEA system solution.

The normal NMEA system would have an Actisense Autoswitch connected to two (or more) GPS / Depth sounder units. The Autoswitch adds a special NMEA tag to the data that passes through it to help identify which of these GPS / Depth sounder units supplied the NMEA data.

The autoswitched NMEA output is connected to one of the NMEA Data Multiplexer’s inputs. In this way the highest priority device’s NMEA data is autoswitched into the complete NMEA system and the actual device supplying the NMEA data can be determined (and displayed if required and possible) to help the user.

Why would I want or need an NMEA Data Multiplexer?

The NMEA 0183 standard allows any suitably designed marine electronic device to share its gathered information with any other device on a vessel. Unfortunately, there is one very large drawback with this standard – only one device on a connected network can actually send data (a single ‘talker’ device), with multiple devices (determined by the current limit of the sending unit) listening to that data (multiple listeners).

If the vessel owner has an instrument that ideally requires the data output of two or more devices, for example a chart plotter, then the owner has no alternative but to settle on connecting only the most important device, usually the GPS.

What happens if the owner prefers the vessels gyro compass output to that of the GPS, or requires that the current depth be displayed on the plotted chart to help avoid the possible case of running the vessel aground on a shifting sand bank? The NMEA 0183 standard cannot supply an answer to those questions: “one transmitting / talking device only”.

The Actisense NMEA Data Multiplexer’s can solve all these problems and more with their simple, easy and flexible designs.

NBF-2 NMEA Buffer

1 in and 6 out: How can there be 6 outputs when there are only 5 grommets?

To make the Actisense NMEA Buffer module highly cost competitive, the module case only has 5 ‘waterproof’ grommets. What grommet is used for what purpose is entirely flexible and up to the user, but it has been designed thus:

1 x battery power input
2-core cable (bottom grommet)

1 x NMEA data input
2-core twisted pair cable (top left grommet)

1-6 x NMEA data outputs
Utilise the 3 remaining grommets as required.

When more than 3 outputs are required, multi ‘twisted pair’ cable is required to share the 3 output grommets between the 6 outputs.

If it is more practical, any of the inputs or outputs could obviously be combined together in a multi-core cable and share a cable grommet – the module is totally flexible.

How many NMEA devices can a single output drive?

Whilst the 6 outputs of the NBF-2 are capable of driving up to 60 NMEA 0183 instruments, to maintain the galvanic isolation between each of the NMEA devices, it is recommended to use only one NMEA device per NMEA output.

If all the NMEA 0183 devices connected to a particular NMEA output are proven to have a correct NMEA 0183 opto-isolated input, then it is possible to connect one NBF-2 output to multiple NMEA devices and still maintain galvanic isolation. However, this is the only condition where multiple NMEA 0183 devices per NBF-2 output is recommended.

When using multiple NMEA devices per output, the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.

Why would I want or need a NMEA Buffer?

There are a number of reasons why an NMEA Buffer is very useful, or absolutely necessary on any size of vessel:

A) Most NMEA instrument outputs are only capable of driving one, or possibly two receive inputs of other instruments. If the output NMEA data is required by more devices, then the NMEA data must be buffered before splitting it to the individual instruments. If not, the NMEA data can become corrupted as the signal quality degrades below the required level.

The Actisense NMEA Buffer module will perform this buffering task simply and efficiently.
Whilst the 6 outputs of the NBF-2 are capable of driving up to 60 NMEA 0183 instruments, to maintain the galvanic isolation between each of the NMEA devices, it is recommended to use only one NMEA device per NMEA output.

If all the NMEA 0183 devices connected to a particular NMEA output are proven to have a correct NMEA 0183 opto-isolated input, then it is possible to connect one NBF-2 output to multiple NMEA devices and still maintain galvanic isolation. However, this is the only condition where multiple NMEA 0183 devices per NBF-2 output is recommended.

When using multiple NMEA devices per output, the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.

B) Ground problems can arise when multiple devices are wired together, causing interference and/or excessive current drain from the vessel’s batteries (which can result in damage).
To avoid this, each of the NBF-2 NMEA outputs use the Actisense ISO-Drive design that will isolate the NMEA device connected each of the NMEA outputs from the NBF-2 ground, and from the NMEA 0183 device supplying the data.

This keeps all NMEA 0183 devices isolated from each other, and prevents any ground loops from being made. Without ground loops, all the NMEA 0183 devices are safe from being damaged from ground loops currents.

This allows the installer to connect up the NMEA 0183 system without the need to worry about what devices are true NMEA 0183 devices (with opto-isolated inputs) and without worrying about resulting ground loops.

NBF-1 NMEA Buffer

1 in and 6 out: How can there be 6 outputs when there are only 5 grommets?

To make the Actisense NMEA Buffer module highly cost competitive, the module case only has 5 ‘waterproof’ grommets. What grommet is used for what purpose is entirely flexible and up to the user, but it has been designed thus:

1 x battery power input 2-core cable (bottom grommet)

1 x NMEA data input 2-core twisted pair cable (top left grommet)

1-6 x NMEA data outputs Utilise the 3 remaining grommets as required

The 3 output grommets can be used directly with any mixture of 3 outputs (RS422 or RS232).

When more than 3 outputs are required, multi ‘twisted pair’ cable is required to share the 3 output grommets between the 6 outputs.

If it is more practical, any of the inputs or outputs could obviously be combined together in a multi-core cable and share a cable grommet – the module is totally flexible.

How many NMEA devices can a single output drive?

The exact number of NMEA 0183 devices / instruments that the NMEA Buffer module is capable of driving will depend on the cable length to all the devices supplied, the quality of the cable used, and the device input circuitry.

Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.

An RS422 output is typically capable of driving up to 8 devices / instruments, and even more under ideal conditions.

An RS232 output can typically drive 2 devices (limited by the RS232 specification).

This gives a total device drive count of typically 36, and even more under ideal conditions.

Why would I want or need an NMEA Buffer?

There are a number of reasons why an NMEA Buffer is very useful, or absolutely necessary on any size of vessel:

A) Most NMEA instrument outputs are only capable of driving one, or possibly two receive inputs of other instruments. If the output NMEA data is required by more devices, then the NMEA data must be buffered before splitting it to the individual instruments. If not, the NMEA data can become corrupted as the signal quality degrades below the required level.

The Actisense NMEA Buffer module will perform this buffering task simply and efficiently.

The ‘1 in, 6 out’ buffer version is typically capable of driving up to 36 instruments – the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.

B) Ground problems can arise when multiple devices are wired together, causing interference and/or excessive current drain from the vessel’s batteries. To avoid this, the NMEA output from the supplying instrument must be isolated from that of the receiving instrument inputs.

The Actisense NMEA Buffer module will isolate the receving device from all the output devices using full galvanic Opto-isolation circuitry.

As all NMEA instruments are required by the NMEA 0183 specification to have Opto-isolated inputs, the Actisense NMEA Buffer outputs are not required to be Opto-isolated to completely remove the common ground issues.

USG-1-485 USG to RS485 Gateway

How many RS485 devices can the USG-1’s transceiver handle?

The USG-1’s transceiver is capable of handling connection of up to 32 RS485 devices.

When connecting multiple RS485 devices, the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and RS485 device inputs not meeting the RS485 specifications will reduce the maximum number of devices drivable.

Why would I want or need an isolated USB to RS485 gateway?

When software running on a PC needs access to RS485 network data, or alternatively, may need to send data to the RS485 network, a communication port needs to be created. However, until the USG-1-485, there was no solution that worked in every case.

The Actisense USB to RS485 (USG-1-485) Gateway developed out of the requirement to solve 3 fundamental problems with interfacing the industry RS485 communications to a PC:

A) Ground loops. When the PC and the RS485 system have different ground potentials (or are totally different ground altogether), data can become corrupted and permanent damage can occur (to the PC and RS485 device).

B) Different standards. When you buy a standard USB to serial converter, they normally provide PC standard RS232 port, whereas RS485 uses a bi-directional signaling system. This means that a standard USB to serial converter is incompatible with RS485 / IEC 61162-2 that use the RS485 driver type.

C) The PC has no serial port. Most modern PCs do not come with serial ports any more as these are being replaced by the new standard of USB. Furthermore, RS485 signals are not directly compatible with standard PC serial ports.

Solution for problem A – Ground loops

The primary problem encountered when using a standard USB to serial converter (or a standard RS232 port) is that the ground of the PC is then shared with the RS485 system ground.

PCs are often powered from a mains inverter, generator set or direct from mains supply when in dock, whereas the marine electronics are normally connected to the current battery set.

This means that when you connect the two systems together, you are joining two different power systems. This can result in no visible problems at first, but more often it results in one of three consequences:

1. Data corruption – the data becomes garbled as the electrical data signal now floats on a noisy ground current flowing between two systems.

2. The PC crashes intermittently as ground currents flow across its sensitive electronic circuitry. This can cause permanent damage.

The USG-1-485 solves all these problems by providing a safe, opto-isolated barrier between the two systems. Because the signal travels across this barrier as light, the signals do not share the same ground, and safety is assured as no current can flow between the two power systems. In addition, a built-in power isolator completes the isolation.

Solution for problem B – Different standards

PC serial or “COM” ports use the RS232 standard. This uses a ground and a receive pin to get data from a connected system. Data is sent as voltages referenced to ground on a single transmit line. This type of drive is known as “single-ended”.

In contrast, NMEA 0183 systems use a “differential” system, where a “Positive” data line and a “Negative” data line move in opposition to each other.

Many installations without isolated outputs have been seen where the negative data line on a differential drive system has been connected to the ground of the PC. If you’re lucky, this may work, but if not, you will either simply get no data, or at worst, damage your equipment.

The USG-1-485 solves this by using ingenious circuitry unique to Actisense in both it’s “Listener” (receiver) circuit and its ISO-Drive “Talker” (transmitter) circuit. These circuits are compatible with both RS232 and NMEA 0183.

Solution for problem C – PC has no serial port.

Many laptop and desktop PCs do not come equipped with RS232 type serial ports any more (which could be converter to an RS485 type using a converter). The USG-1-485 solves this by creating an industry standard RS485 port from any PC USB port.

This port appears on the PC system as a regular “COM” port, and so can be used with all standard navigation and display software. This allows a connection to be up and running in minutes.

DST-1 DST Module

What special features does it have?

This is a very open-ended answer because, as the Actisense Active DST Module software can be updated, the list of special features can be extended or modified when required – by Actisense, or a particular customer.

Why would I want or need an Active DST Module?

A) the situation where an existing depth sounder’s transducer is still working but the display unit controlling it is faulty and/or too old.

B) the situation where the user requires to use a non-Airmar transducer, but still wants all the benefits of the active transducer.

The Actisense Active DST Module, working with a large range of transducers, can supply high quality depth, speed, distance log and water temperature information (in NMEA 0183 format) to a chart plotter, radar or even an onboard PC.

The Active DST Module design is very flexible, having been tried and proven with a large range of transducers. This list continues to grow and currently includes, but is not limited to:

Airmar 170 kHz, 200kHz and 235kHz (In-hull, Thru-hull, Transom mount)

Skipper 200 kHz (In-hull)

EchoPilot Marine 150 kHz (In-hull)

NASA Marine 150 kHz (In-hull)

The proven Actisense depth sounding algorithm, working with, for example an Airmar transducer, can provide the best-in-class tracking of the seabed – capable of tracking the seabed down to 0.3 metres (1 foot) and up to 200 metres (660 feet) and still outperform other depth sounders at speeds up to 50 knots (57 MPH).

Added to this is the ability to interface to a standard paddle-wheel log transducer and calculate the vessel’s speed and the trip distance travelled (log).

The final ability of interfacing to a standard temperature transducer, to calculate the current water temperature, completes the picture of this powerful, all-in-one system.

Simply install the Actisense Active DST Module (and the associated transducers if not already fitted) and connect it to your NMEA 0183 network – normally through an NMEA Multiplexer or an NMEA Buffer – and all the NMEA data will be instantly available to any NMEA devices that require i

"With a staff of some of the sharpest engineering minds in the industry and a relentless drive to innovate, Actisense has achieved a standard of quality and reliability most companies only hope for. Their innovative designs and top-quality manufacturing result in a broad range of solutions infused with durability and value. We are proud to share in their success and without hesitation, recommend Actisense solutions to all of our customers."Peter Braffitt, General Manager, GEMECO Marine Accessories